TORQUE CONVERTER GP 7S8598 - Caterpillar

Function
The double-acting hydraulic apron cylinder gives positive force to raise or lower the bowl apron. The apron cylinder is enclosed by the gooseneck and is mounted on the draft tube.Operation
Cylinder rod extension raises the apron and retraction lowers the apron. An apron sequence relief valve protects against excessive rod end oil pressure by routing rod end oil to the cylinder head end when the apron is forced up.In addition to RAISE and LOWER, the apron control lever has FLOAT and HOLD positions. In HOLD, the apron locks at any opening necessary to control the material ejection rate.In FLOAT, the apron's rise and fall is determined by the external forces at the apron lip.Testing and Adjusting
Raise the bowl cutting edge 6 to 10 in. (152 to 254 mm) above the ground. Position the apron so that it is open approximately 15 in. (381 mm). Mark the lower edge of the apron on the bowl. Measure the drift of the apron relative to the front edge of the bowl. The apron should not drift more than .25 in. (6.4 mm) per minute. Possible causes of excessive leakage:1. Worn cylinder piston seals.2. Worn control valve spool.3. Apron sequence relief valve wear.